1. Technical Field
The present invention relates to a liquid ejecting head module including a liquid ejecting head which ejects liquid from a nozzle opening, and a liquid ejecting apparatus, and in particular relates to an ink jet type recording head module and an ink jet type recording apparatus.
2. Related Art
As a liquid ejecting apparatus represented by an ink jet type recording apparatus such as an ink jet type printer or a plotter, there is an apparatus having a liquid ejecting head module. The liquid ejecting head module includes a liquid ejecting head detachably attached to a fixing member and the liquid ejecting head can ejects a liquid as liquid droplets from a liquid storage unit such as a cartridge or a tank in which the liquid is stored.
The liquid ejecting head includes a pressure generation chamber communicating with a nozzle opening provided at a nozzle plate, and a pressure generation unit which causes a pressure change in the ink inside the pressure generation chamber and ejects liquid droplets from the nozzle opening. Then, pressure generation units mounted on the liquid ejecting head include, for example, units using a vertically oscillating type piezoelectric element, a bending vibration type piezoelectric element, a heating element and an electrostatic force.
The ink ejected from the liquid ejecting head has viscosity suitable for the ejection according to a type of ink. Since the viscosity of the ink has a correlation with the temperature, the ink has a property in which the viscosity is high when the temperature is low and the viscosity is low when the temperature is high. Thus, it is necessary to correct a driving signal which drives the pressure generation unit of the liquid ejecting head according to the viscosity which is changed by the temperature of the ink (see, for example, JP-A-6-31934 and JP-A-2009-56669).
It is preferable that the temperature of the ink be measured in a state immediately before being ejected, that is, in the vicinity of the nozzle opening. However, it is difficult to measure the temperature of the ink in the vicinity of the nozzle opening by providing a temperature sensor at the nozzle plate, from a viewpoint of manufacturing, stiffness or the like of the nozzle plate.
Then, it is also considered to measure the temperature of the ink in the upstream side rather than in the vicinity of the nozzle opening. However, an error occurs the measured temperature and the temperature of the liquid inside the pressure generation chamber immediately before being ejected. When the driving signal is corrected, based on the inaccurate temperature of the ink, there is a problem in that the correction of the driving signal suitable for actual viscosity of the ink may not be carried out and thereby degraded ejection characteristic is may cause a printing quality to be deteriorated.
In addition, the problem is not limited to the ink jet type recording head module and also similarly exists in a liquid ejecting head module ejecting liquid other than the ink.